New Posts New Posts RSS Feed: New PY Website
  FAQ FAQ  Forum Search   Register Register  Login Login

New PY Website

 Post Reply Post Reply Page  <1 678910 14>
Author
AlexM View Drop Down
Really should get out more
Really should get out more


Joined: 10 Jan 06
Online Status: Offline
Posts: 857
Post Options Post Options   Quote AlexM Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 12 at 2:12pm
0.7 Is very good c.f.
Take a look at Yorkshire Dales implementation of the figures that’s what we’ve followed:
c.f. 0.1 used 33% of the change
c.f. 0.2 used 66% of the change
c.f 0.3+ used 100% of the change
Interesting to note you’ve got similar results to L&L….
Laser down we’re 1074 (something I wasn’t expecting at all!! I would have bet anything on this going up)
RS 400 down we’re also 942

Are you over in Southport? You could class our lakes similar and we could use some of your high c.f. classes e.g GP14. I think this option was originally mentioned when the site got setup?
Back to Top
MattHarris View Drop Down
Groupie
Groupie
Avatar

Joined: 03 Oct 06
Location: United Kingdom
Online Status: Offline
Posts: 94
Post Options Post Options   Quote MattHarris Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 12 at 4:25pm
Yeah I'm from Southport, not sure on the lakes similarities.  I agree they're both small but with the islands we find that we can be quite restricted and we sadly never get the same blasting in the 400 without running out of space. 
If you want to use any of the figures please feel free, although I think we'd get some grief trying to use the L&L ones, especially the enterprise one.  Having said that the figures are quite similar although.
 
With regards to the yorkshire dales idea i think we'd have to change them based on the confidence wording to get more traction with members (0.2-0.3, 0.4-0.6 and 0.7+) but thats for another day entirely.  For the moment I'm just making sure its done ready for the return and for bar discussion over winter so the idea has been thoroughly chewed over before maybe starting a discussion next year.
Phantom 1175 - Alice

http://www.thelostpenguin.co.uk
Back to Top
marke View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 16 Jun 08
Location: United Kingdom
Online Status: Offline
Posts: 209
Post Options Post Options   Quote marke Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 12 at 4:40pm
Matt

Its far too early in the development of the PYS to be worried about 'absolute' values of c.f.  With a few years experience the c.f will be modified and tuned and then we can start talking about absolute thresholds.  For now the message for clubs should be that a cf of >0.5 is bloody good and should give a lot more confidence than a class with a cf of 0.1.  Keith's approach at Yorkshire Dales seems like a good way to approach it at this stage.

We started adjusting our PYs locally a couple of years ago, and on all sorts of measures we can demonstrate that the racing has got closer.  There was a little bit of grumbling when it was brought in - but much less than I expected and once you have made the move its a lot easier to keep it going. 

mark
Back to Top
Hector View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 10 May 04
Location: Otley, Yorkshire
Online Status: Offline
Posts: 750
Post Options Post Options   Quote Hector Quote  Post ReplyReply Direct Link To This Post Posted: 24 Oct 12 at 10:25pm
I think the RYA have named the 'confidence factor' badly. It smacks of error / inaccuracy when it's not meant to. I think it should have been named Stability Factor as that is a more accurate description of what it is. 

Mark and I are clearly on the same page RE application of the PYS. 
The outcome of our changes has been much closer results, and a little more variety in boats in the top 5. Same ones seem to win - dependent on wind, but the top boats from other fleets are more likely to beat the not so good sailors from the 'favoured boat' - which I'd say is a good thing.

We didn't just decide to 'do our own thing'. I attended two talks / meetings on the subject by Andy Wilbroe / Bas (at The Dinghy Show).
The logic regarding confidence factors as I understand it following those talks is described on our website and pasted in part below

NOTE: They (RYA) have also give a confidence level.  'Confidence' refers to the stability of the number - not its accuracy. Confidence in the stability of PNs obviously rises as more race data is input and as we are in the first year of this process we decided to recognise the likelihood of increasing confidence, and so the Sailing Committee has agreed that the changes recommended by the RYA for YDSC will be 'damped' by applying  a % adjustment. Depending on the confidence level the % of any change applied will be as follows   

0.0 - 0.1 = 33.33%       0.2 - 0.3 = 66.67%       0.4 ++++ = 100%

The percentages we chose were partly as we had no high confidence figure after one years input, and secondly that to do less would have let some key classes escape any worthwhile alteration, and third, the figures are correct - they just may not be stable. The Highest c.f. was the Laser at 0.4, and that only moved a paltry 5 points from the standard number so we were Very Confident we could implement that 100%.  The rest followed logically.

I think the RYA have named the c.f. badly. It smacks of error / inaccuracy when it's not meant to. I think it should have been named Stability Factor as that is a more accurate description of what it is. 

I'll post our latest PNs here soon - once agreed at club. Our Laser figure drops slightly - Like Mark, I'm  suprised at that - but others have dropped more so overall they gain on most other classes. With very much increased / high confidence figures for more classes, we'll be applying more of the change from National PN to Yorkshire Dales PN for our next series, and no-one has complained about it at all, on the contrary, most comments are very positive.



Edited by Hector - 24 Oct 12 at 10:40pm
Keith
29er 661 (with my daughters / nephew)
49er 688 (with Phil P)
RS200 968
Vortex (occasionally)
Laser 2049XX
Back to Top
JimC View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 17 May 04
Location: United Kingdom
Online Status: Offline
Posts: 6286
Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 12 at 6:19am
I dunno, confidence seems like a reasonable term to me. The wilder the data in all respects the less confidence you have it it. I don't see a connection with stability at all.

Edited by JimC - 25 Oct 12 at 6:21am
Back to Top
marke View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 16 Jun 08
Location: United Kingdom
Online Status: Offline
Posts: 209
Post Options Post Options   Quote marke Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 12 at 9:46am
From a scientific perspective I think it is a confidence factor (in this application I think consistency is part of the accuracy assessment - unless of course you are making all RS400 sailors at your club tow a bucket!).  In the interests of avoiding argument it could perhaps be called the "anti-grumbling factor" or "getting the nay-sayers to shut up factor" - or perhaps following the Duckworth/Lewis approach from cricket and call it the Wibroe/Edmonds factor. Smile

We are seeing exactly the same impact from local PY adjustment as Keith - "Same ones seem to win - dependent on wind, but the top boats from other fleets are more likely to beat the not so good sailors from the 'favoured boat' - which I'd say is a good thing".  In several of our trophy races this year we have 5 or more different classes in the top 10, and in our overall club championship (series of ~12 trophy races held in conditions throughout the year) we had 8 different classes in the top 10 (including for the first time in a decade a well-sailed laser).  

Edited by marke - 25 Oct 12 at 9:54am
Back to Top
AlexM View Drop Down
Really should get out more
Really should get out more


Joined: 10 Jan 06
Online Status: Offline
Posts: 857
Post Options Post Options   Quote AlexM Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 12 at 9:55am
I like that - "anti-grumbling factor" or "getting the nay-sayers to shut up factor"   

I'm still amazed about the PY for the Laser

We've changed ours for this Autumn/before Christmas series, will have a review at 1st Jan for 2013 and then probably see where we are when the new RYA PY's come out.
Back to Top
Hector View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 10 May 04
Location: Otley, Yorkshire
Online Status: Offline
Posts: 750
Post Options Post Options   Quote Hector Quote  Post ReplyReply Direct Link To This Post Posted: 25 Oct 12 at 1:09pm
From the RYA / PYS site:
The reports page will currently show a list of Portsmouth Numbers based the results a club has uploaded. Each is given a confidence factor based on the volume and quality of the data behind each PN. As the data increases and proposed number becomes more stable it will be given the RYA seal of approval and a high confidence factor.

So to get a high confidence requires a stable number - hence the c.f figure is a measure of stability.
Nuances aside, I stick by my assertion that stating you have low confidence in a figure smacks of possible error, and if 'some people' want to resist the change, they can more easily hang their argument on that point.


The RYA site goes on:

ALL CLUBS are reminded that this number may still not be perfect and the club will still need to take the ultimate decision as to if they use that number and or an adjustment of that number.
Hence the YDSC decision to recognise the low stability of most of last years Club numbers and hence damp the adjustment from National numbers. This year there is far higher confidence from the PYS site, and after a year of racing and results we are also more confident ourselves.

To simplify my point  - 
Are the RYA confident that the process accurately and correctly calculates current Club PNs?   YES
(I understand the process is based on YR2 but adjusted with algorithms that take into account data spread, volume etc).

Are the RYA confident that the figure produced are likely to remain stable? DEPENDS
(On quality and volume of data)





Edited by Hector - 25 Oct 12 at 1:11pm
Keith
29er 661 (with my daughters / nephew)
49er 688 (with Phil P)
RS200 968
Vortex (occasionally)
Laser 2049XX
Back to Top
AlexM View Drop Down
Really should get out more
Really should get out more


Joined: 10 Jan 06
Online Status: Offline
Posts: 857
Post Options Post Options   Quote AlexM Quote  Post ReplyReply Direct Link To This Post Posted: 30 Oct 12 at 12:31pm
Is the data graph for the class working for anyone else? I get all the info apart from the actual line.

Alex
Back to Top
MattHarris View Drop Down
Groupie
Groupie
Avatar

Joined: 03 Oct 06
Location: United Kingdom
Online Status: Offline
Posts: 94
Post Options Post Options   Quote MattHarris Quote  Post ReplyReply Direct Link To This Post Posted: 02 Nov 12 at 1:10pm
Just checked and it looks ok on mine.  Whilst checking I also noticed that I've got an "RYA Technical Approved" stamp on the results for the GP (0.7 cf) and Mirror Single Handed (0.6 cf).  Not sure whether this is a new feature or just I've not noticed it before.
On an aside we had a sailing committee meeting last week at which I brought up the PYS website.  Was interesting to see the mix of responses across the sailors.  Ultimately they decided not to adopt the numbers and stick with the RYA list and have another discussion in 12 months with another years data on hand, we should hopefully have a few more stamps of approval by then too.


Edited by MattHarris - 02 Nov 12 at 1:10pm
Phantom 1175 - Alice

http://www.thelostpenguin.co.uk
Back to Top
 Post Reply Post Reply Page  <1 678910 14>

Forum Jump Forum Permissions View Drop Down

Bulletin Board Software by Web Wiz Forums® version 9.665y
Copyright ©2001-2010 Web Wiz
Change your personal settings, or read our privacy policy